Stiffening assembly for a fuel tank

ABSTRACT

A tank assembly and a stiffening assembly include first and second inserts and an elongate coupler. The inserts comprise a base having flange, a head, and a neck. The elongate body has first and second couplers at respective first and second ends of the body, each coupler including a pocket sized to receive the head of a respective one of the inserts. The related method include forming a fuel tank such that the tank wall carries at least a first and second insert, locating a rigid connector within the tank interior aligned with the first and second inserts, the connector including a first coupler and a second coupler, and coupling at least a portion of the first insert with the first coupler and at least a portion of the second insert with the second coupler to limit movement of the two wall portions relative to each other.

CROSS-REFERENCE

This application claims the benefit of U.S. Provisional Application Ser.No. 62/106,404 filed on Jan. 22, 2015, entitled “STIFFENING ASSEMBLY FORA FUEL TANK,” the entire contents of which are incorporated herein byreference.

TECHNICAL FIELD

The present disclosure relates generally to a structure supporting afuel tank under pressure.

BACKGROUND

Fuel tanks for automotive vehicles have been made from metal and plasticmaterials. Fuel tanks are formed in various sizes and shapes as requiredfor the various applications in which they are used. Fuel tanks used inpassenger vehicles must meet certain requirements relating to, forexample, resistance to rupture upon impact and permeability tohydrocarbons in fuel vapor. Typical plastic fuel tanks include a singlewall of material and that wall may be formed from a single material ormultiple layers of different materials. Particularly in fuel tanks,there is a need to make containers having more than one wall or layer ofdifferent materials in order to meet various requirements, for examplewith respect to mechanical stability and resistance to higher pressuresin modern systems. Up to now the making of such containers requirescomplex multi-step manufacturing methods.

SUMMARY

The present disclosure provides a stiffening assembly for a fuel tank.The stiffening assembly includes first and second inserts for the wallof a fuel tank, and an elongate coupler. The inserts each comprise abase having flange, a head, and a neck coupling the base to the head.The neck may have a portion that is narrower than at least a portion ofthe head. The elongate body has first and second couplers at respectivefirst and second ends of the body, each coupler including a pocket sizedto receive the head of a respective one of the inserts.

According to more detailed aspects, each insert may be integrally formedin one piece. The heads of the inserts may include voids at their distalends. The inserts may be partially hollow, and may include a cavityopening at the base. The inserts may include ribs projecting into thecavity. The couplers can be separately formed and attached to theelongate body, the couplers and body including corresponding tabs anddetents for attachment. The elongate body may define first and secondopenings at the first and second ends, the first and second openingsreceiving the first and second couplers. The pockets may be defined by aplurality of fingers, the plurality of fingers being moveable between afirst state and a second state, the plurality of fingers moving radiallyinwardly from the first state to the second state. The first and secondopenings are sized to cause the plurality of fingers to move to thesecond state as the fingers are received within the openings. Theelongate member may include two tubular members defining the first andsecond ends and at least a third end, wherein the stiffening assemblyfurther comprises a third insert and a third coupler at the third end.

A fuel tank assembly according to the present disclosure includes a fueltank having a wall defining a tank interior, and a stiffening assemblyas described herein. A first exterior portion of the tank wall carriesthe first insert and a second exterior portion of the wall carries thesecond insert, and wherein the body and couplers are received within thetank interior. Here, the wall may be interposed between the inserts andthe couplers.

The present disclosure also provides a method of manufacturing a fueltank. The method may include the steps of forming a fuel tank, whereinthe tank carries at least a first and second insert, locating a rigidconnector within the tank interior, aligned with the first and secondinserts, the connector including a first coupler and a second coupler,and coupling at least a portion of the first insert with the firstcoupler and at least a portion of the second insert with the secondcoupler. The connector spans between two spaced apart wall portions ofthe tank to limit movement of the two wall portions relative to eachother.

According to more detailed aspects, the forming step may furthercomprise overmolding the insert while the fuel tank is in a parisonform. The forming step may also further comprise shaping a tank wallcarrying the insert so that the insert defines a projection that extendsat least partially radially inwardly into a tank interior. In one form,the fuel tank is formed in a mold having portions moveable between openand closed positions, and the step of coupling the insert with the firstcoupler is accomplished by movement of the mold portions toward theirclosed position. The interior of the parison may be accessed during thetank forming process to allow insertion of the connector into theparison interior, e.g. by cutting or tearing the parison into twoportions. The method may also include the step of coupling the first andsecond couplers to the connector. The first coupler may be coupled tothe connector simultaneously with coupling the first coupler to thefirst insert.

BRIEF DESCRIPTION OF THE DRAWINGS

The following detailed description of preferred embodiments and bestmode will be set forth with reference to the accompanying drawings, inwhich:

FIG. 1 is an exploded view of a portion of a fuel tank and a stiffeningassembly within the fuel tank;

FIG. 2 is a perspective view of the stiffening assembly of FIG. 1 in apartially assembled state;

FIG. 3 is a perspective view of the stiffening assembly of FIG. 1 in afully assembled state;

FIGS. 4A-4C illustrate additional embodiments of the stiffeningassembly; and

FIG. 5 is a partial, cross-sectional view of a portion of the stiffeningassembly and part of a fuel tank wall along section lines 5-5 of FIG. 3.

DETAILED DESCRIPTION

Referring in more detail to the drawings, FIG. 1 illustrates a portionof a fuel tank 10 (in a parison form) and a stiffening assembly 12coupling two portions 14, 16 of a fuel tank wall 18. The stiffeningassembly 12 provides structural support for the fuel tank 10 andminimizes deformation of the shape of the fuel tank (e.g., due totemperature changes, pressure changes, or both).

The fuel tank wall 18 defines an enclosed volume or interior 20 forcarrying liquid fuel. The wall 18 may have any suitable thickness;further, the thickness of the wall may vary depending on the location inthe tank 10. And the tank may be comprised of any suitable material,such as (but not limited to) a multi-layer plastic construction havingone or more structural layers, one or more adhesive layers, and one ormore vapor barrier layers.

The stiffening assembly 12 comprises two or more inserts 30 and aconnecting assembly 32. As will be explained below, the inserts 30 arecarried by the fuel tank wall 18, and the connecting assembly 32 spansbetween and couples one insert to the other thereby stiffening orsupporting two connected or adjoined regions or portions 14, 16 of thefuel tank wall.

The inserts 30 may be identical; therefore, only one will be describedbelow. The insert 30 has a base 36, a reduced diameter neck 38 axiallyextending from the base, and a head 42 extending from the neck. Theillustrated base has a generally annular shape and is partially definedby a radially outwardly extending flange 46. In one embodiment, theperiphery of the flange 46 is circular; however, the base 36 and/orflange 46 may have different shapes as desired. In at least someimplementations, at least a portion of the flange 46 is radially widerthan a portion of the neck 38.

The neck 38 may radially narrow as it extends axially from the base 36,providing a generally conical or frustoconical shape. Or as in theillustrated embodiment, the neck may be curved between the base and headproviding a partially hyperbolic shape. In some implementations, atleast a portion of the neck 38 is radially narrower than a portion ofthe head 42. The neck 38 may be circumferentially continuous, ifdesired, or it may have recesses or other voids formed in it to improveconnection of the tank to the insert 30.

The head 42 is connected to the neck 38 extending axially awaytherefrom, and at least a portion of the head 42 may be radially widerthan at least a portion of the neck 38 adjacent to the head. In theimplementation shown, the head is generally spherical; however again,this is merely an example. Other shapes are possible. The head 42 mayhave one or more voids 52 at a distal end 54. The voids 52 may becavities or blind holes, through holes, or any combination thereof. Forexample, the cross-section shown in FIG. 5 illustrates the voids 52 asblind holes.

The base 36, neck 38, and head 42 of the insert may be integrally formedin one piece of material, such as by molding (e.g., a unibodyconstruction). In at least one implementation, the insert 30 is formedof a polymeric, composite, or metal material.

The insert 30 may be at least partially hollow—having a cavity 56opening at one side 41 of the base and extending towards the head 42(see also FIG. 5). As will be described in greater detail below, thecavity 56 may be used to carry the insert 30 in a manufacturing mold sothat the insert may be incorporated into a parison of the fuel tank 10.The cavity may be any suitable shape; and in some implementations, theinsert 30 may not have a cavity.

FIG. 5 further illustrates that the insert 30 may have one or more ribs58 that extend inwardly and define part of the cavity 56. To reinforcethe strength of the insert 30, the ribs 58 may extend at least partiallycircumferentially and/or at least partially from the base 36 towards thehead 42.

The insert 30 may include cavities or other voids, including openingstherethrough, in one or more of the base 36, neck 38, and head 42 tofacilitate connection of the insert to the fuel tank wall 18. Forexample, according to one embodiment shown in FIG. 5, the insert maycomprise one or more circumferentially-spaced through holes 50 on thebase 36 to further facilitate bonding of the insert to the parison fueltank during manufacturing. Other embodiments do not comprise holes 50.The insert 30 is adapted to cooperate with the connecting assembly 32 tointerconnect spaced apart portions 14, 16 of the fuel tank wall.

Returning to FIG. 1, the connecting assembly 32 includes a cylindrical,tubular body 64 extending from a first end 66 to a second end 68 and twocouplers 62. Each end 66, 68 may have an opening 70 a, 70 b extendingfrom the respective end axially inwardly. In the illustrated embodiment,the body 64 is hollow and the openings 70 a, 70 b are in communicationwith one another; however, this is not required. One or morecircumferentially spaced detent elements 76 may be provided in the body64 at or adjacent to the first end 66 and one or more similar detentelements may be provided at or adjacent to the second end 68. Forexample, in the illustrated embodiment, six circumferentially spaceddetent elements 76 are shown at each end. The detent elements 76 areshown as circular through-holes; however, this is merely an example andother implementations are possible—e.g., the elements 76 need not becircular nor need the elements pass entirely through the support body 64(e.g., the element 76 may be a cavity or depression extending radiallyoutwardly from an inner surface 78 of the body 64. Or for example, thedetent elements could be inwardly extending protrusions adapted tocouple to openings or cavities on the connectors 62.

In FIG. 1, the body 64 is straight; however, other implementations alsoexist (see FIGS. 4A, 4B, 4C having support bodies 64′, 64″, 64′″,respectively). For example, the support may be curved or angled. It mayhave a T-shape, a Y-shape, a cross-shape, an X-shape, etc. (e.g., havingthree or more openings and passages). These of course are examples, andother embodiments also exist.

As shown in FIGS. 1-3, in at least one embodiment, a separate connector62 is coupled to each end 66, 68 of the body 64, and the connectors ateach end 66, 68 of the body may be identical, so only one connector 62will be described in detail hereafter. The connector 62 comprises acollar 80, a first coupler 82 and a second coupler 84. The first coupler82 is adapted to interconnect the connector 62 and the fuel tank 12while the second coupler 84 is adapted to interconnect the connector 62to the body 64. The collar 80 is sized to be received within the opening70 a (or 70 b) by a sliding or interference fit. The collar 80 is shownhaving an annular, cylindrical shape, but of course, other shapes arealso possible.

In the illustrated embodiment, the first coupler 82 includes one or morefingers 86 attached at one end 90 to and extending from the collar 80 toa free end 94 (six fingers are shown, although any number may be used).The fingers may extend generally axially from the collar and may beradially inclined so that the free ends 94 extend radially outwardlyrelative to the collar 80. The fingers 86 may also be flexible, orpivoted relative to the collar 80, such as about a living hinge definedat the fixed end 90, so that the free ends 94 may move radiallyinwardly. Hence, the fingers 86 may have a first state where thedistance between the inner surfaces of the free ends of the fingers isgreater than in a second state of the fingers when at least a portion ofthe fingers are flexed or moved inwardly. In the implementation shown,the fingers 86 include a narrow portion 88 at the fixed end 90 leadingto a wider portion 92 that defines the free end 94. Each finger 86 maybe provided in or biased to a radially outwardly position and isflexible to move inwardly when a sufficient force is applied to it. Thesix fingers 86 may be evenly, circumferentially spaced around the collar80. The inner surface of each finger may be concave so that the fingerscollectively define a pocket 96 (see also FIG. 5). The pocket 96 isadapted to receive at least a portion of the head 42 of the insert 30,as will be described later.

In the illustrated embodiment, the second coupler 84 includes multipleprotrusions 100 also carried by and, in at least some implementations,cantilevered from the collar 80 so that they have a fixed end 102 and afree end 104 (six protrusions are shown although any number may beused). The protrusions may be evenly spaced around the collar and may bealternated with the fingers 86, if desired. Of course, otherarrangements may be used as desired. Like the fingers 86, theprotrusions 100 may extend axially and radially outwardly from theirfixed ends 102 toward their free ends 104. In one embodiment, theprotrusions 100 terminate where the wider portion 92 of the fingers 86begin and a gap 106 is provided surrounding the protrusions 100 so thatthe protrusions are generally independent of the fingers. In at leastone embodiment, each protrusion 100 is provided in or biased to aradially outwardly inclined position having at least a portion thatextends radially outwardly farther than the adjacent portion of thefingers 86. Each protrusion 100 may be flexible so that at least aportion is moveable or may be bent radially inwardly; e.g., flexing ator near the collar 80, such as about a living hinge provided between thecollar 80 and protrusion 100. And each protrusion may be resilient toreturn radially outwardly at least partially back to its unflexedposition when a force on the protrusion is sufficiently reduced orremoved.

FIGS. 1-3 collectively illustrate at least a portion of a manufacturingprocess for a fuel tank. In one embodiment, the tank 10 and its wall 18may be molded from a polymeric material in a mold having two halves thatdefine a mold cavity that defines the outer shape of the fuel tank. Inthe fuel tank forming process, the mold halves may be opened and theinserts 30 may be positioned within the mold halves before the polymericmaterial is provided into the mold cavity. In at least someimplementations, the inserts 30 are oriented with the base 36 and/orcavity 56 engaged with or carried by each mold half and the head 42extending inwardly into the mold cavity. The inserts 30 may be providedin pairs, with a first insert carried by one mold half and a secondinsert carried by the other mold half and aligned with the first insert.Hence, when the mold halves are closed together to define the moldcavity, the inserts 30 are moved toward each other and remain aligned(in at least some implementations).

An extruded parison used to form the fuel tank may be provided into themold, between the separated mold halves. Next, the mold halves may be atleast partially closed and pressurized gas (e.g., air) may be providedinto an interior of the parison using a blow pin to pre-blow the parisonoutwardly into the mold cavity. During the expansion, the head 42 andneck 38 of the inserts 30 may be covered with the parison material whichconforms to their shape, and the base 36 may be at least partiallyembedded therein. Thus, the expansion may shape at least a portion ofthe tank wall 18 so that each of the inserts 30 define a projection thatextends at least partially radially inwardly into the tank interior.These projections may be defined by the size and shape of the head 42,the neck 38, and/or even the base 36, as well as well as the thicknessof the parison; thus, for example, the projections may have any desireddiameter(s) (and varying diameters/shape), inwardly extending length,etc.

Thereafter, the parison material may separated into parison halves orportions, such as by cutting or tearing the parison, with one parisonhalf in each mold half. The mold halves then may be opened to expose theinterior of the parison halves. This provides access to the interior ofthe parison so that fuel tank components, such as the connectingassembly 32, may be located within the interior of the parison. One suchmethod of forming a parison and separating a parison into parison halvesin order to locate components therein is disclosed in U.S. patentapplication Ser. No. 12/491,964, the disclosure of which is incorporatedby reference herein in its entirety.

With the mold opened, the connecting assembly 32 is introduced betweenthe mold halves and the parison halves. Here, the connectors 62 areprovided in an initial assembly position, as shown in FIG. 2. In thisinitial position, the collars 80 are at least partially received withinthe connector tube openings 70 a, 70 b, optionally with the protrusions100 received within the respective opening, displaced inwardly andfrictionally engaged with the inner surface 78 of the tubular body 64.In this initial assembly position, the connecting assembly 32 ispositioned between the mold halves with the pockets 96 defined by theconnector fingers 86 being aligned with the heads 42 of the inserts 30.The connecting assembly 32 may be held in this position on an arm (e.g.,a robot arm) or other actuator holding the connector assembly 32 untilthe connectors 62 initially receive the heads 42 between the free ends94 of the fingers 86, and then the arm may be withdrawn from between themold halves so that the mold may be further and eventually, fullyclosed.

While the mold halves close, the heads 42 of the inserts 30 are receivedwithin the pockets 96 of the connectors 62 and the free ends 94 of thefingers 86 eventually engage the tank material overlying the base 36.Further closing of the mold presses the connectors 62 into the tubularbody 64 simultaneously at each end 66, 68, and radially inwardly flexesthe fingers 86 as the fingers are increasingly received within the body64. Upon full closure of the mold, as shown in FIG. 3, the protrusions100 are aligned with the detent elements 76 and the protrusions 100resiliently return radially outwardly to or toward their initial statesuch that a portion of the protrusions 100 extends outwardly into orthrough the detent elements 76. Also, the fingers 86 are received withinthe body 64 sufficiently to radially inwardly displace the fingerssufficiently so that the fingers radially overlap the heads 42 of theinserts 30 so that the heads are trapped within the pockets 96 definedin the connectors 62. The components remain in this position as theparison material is finally formed (e.g. final blow pressure is appliedwithin the parison interior). The material hardens and the formed fueltank 10 is removed from the mold.

In this position, outward movement of the fingers 86 is prevented by theoverlapping tubular body 64, and movement of the body relative to theconnectors 62 is prevented by engagement of the protrusions 100 with thebody 64 from within the detent elements 76. In this way, the head 42 ofeach insert 30 remains trapped in an associated pocket 96, and the fueltank wall 18 portions remain interconnected. So connected, the portions14, 16 of the fuel tank wall that are interconnected by the connectingassembly 32 are inhibited or prevented from any significant movementaway from or toward each other. This is due at least in part to the fueltank wall 18 being securely trapped between the respective heads 42 ofthe inserts 30 and the connectors 62 such that forces tending toseparate the fuel tank walls are transferred to the tubular body 64 (viathe inserts 30 and connectors 62) which may be rigid and substantiallyinextensible.

Further, the stress on the tank 10 from such forces is experienced overa relatively large surface area at the interface between the insert base36 and the tank wall 18 to prevent undue stress on any portion of thefuel tank. By increasing the surface area of the flange 46, the forceson the tank wall can be further dissipated, as desired for a particularapplication. By way of example, forces tending to separate the fuel tankwalls 18 (e.g. expand the fuel tank outwardly) may occur due toincreased pressure within the tank, or the weight of fuel in a full tankacting on the fuel tank wall. Further, temperature increases (bothambient temperature outside of the fuel tank 10 and the temperaturewithin the fuel tank) can decrease the stiffness, rigidity, or strengthof a polymeric fuel tank. Therefore, the fuel tank 10 with thestiffening assembly 12 may be used to contain fluid at increasedpressures and/or with increased temperatures compared to tanks withoutsuch stiffening or connecting features. And, due to the increasedstiffness and rigidity of the fuel tank provided by the stiffeningassembly 12, a thinner fuel tank wall 18 can be used in applicationscompared to fuel tanks 10 without the assembly 12, which may lead to acost savings and, in some instances, a weight savings.

The above described process is one example of a fuel tank formationprocess. Other processes may be used to form a fuel tank with thestiffening assembly 12 therein. For example, a fuel tank may be formedfrom an uncut or undivided cylindrical parison introduced between twoopen mold halves each carrying an insert 30, similar to that describedabove. An arm may introduce a carrier carrying the connecting assembly32 through an open end of the parison aligning the connectors 62 withthe inserts 30. The mold halves may be partially closed, an opposing endof the parison may be at least partially closed using a grippermechanism, and pressurized air may be provided into the parison toinitially and partially expand it. The mold halves may be partiallyclosed until the connectors 62 at least partially receive the heads 42of the inserts 30, as described above. Thereafter, the arm may beremoved leaving the carrier and connecting assembly 32 in place, andthen, the mold halves may be fully closed fully engaging the connectingassembly with the inserts 30, having the parison trapped therebetween.During this process, and even after the mold is fully closed, additionalpressurized air may be provided into the parison—e.g., to maintain theparison open and prevent it from collapsing and to form the parison intothe desired fuel tank shape. Other aspects of this method are disclosedin U.S. Pat. No. 6,712,234, the disclosure of which is incorporated byreference herein in its entirety.

In another assembly example, a fuel tank may be formed from sheets ofmaterial, such as in a vacuum forming or other type of process. Withmold halves opened, material may be provided into both mold halves,overlapping the inserts 30. The material may then be formed into thecavities such as by vacuum forming. As described above, the connectingassembly 32 may be provided between the mold halves before they areclosed so that the connecting assembly 32 is coupled to the inserts 30as the mold halves close to form the fuel tank.

In another example, the connecting assembly 32 is provided into a fueltank and coupled thereto after the tank is formed. In this embodiment,the tank is formed by overmolding the inserts 30 as described above.Once the tank material has hardened, the connecting assembly 32 may belocated within the interior 20 of the tank such as by being insertedthrough a hole in the tank wall 18.

Next, the fuel tank walls 18 may be separated sufficiently to permit theconnecting assembly 32 to be received between the portions 14, 16 of thetank wall that overlie the inserts 30—the connectors 62 not being fullyreceived within the tubular body 64. The connectors 62 may be alignedwith the inserts 30. Then, the fuel tank wall portions may be movedcloser together to push each connector 62 into the tubular body 64 whilealso engaging the heads 42 of the inserts 30 into the body 64 of theconnecting assembly 32, similar to that described above. Once thecoupler 82 is engaged to the insert heads 42 and the coupler 84 isengaged with the body 64, the assembly is complete.

While the forms of the invention herein disclosed constitute presentlypreferred embodiments, many others are possible. It is not intendedherein to mention all the possible equivalent forms or ramifications ofthe invention. It is understood that the terms used herein are merelydescriptive, rather than limiting, and that various changes may be madewithout departing from the spirit or scope of the invention.

1. A stiffening assembly for a fuel tank having a wall, the assemblycomprising: first and second inserts for the wall of a fuel tank, theinserts each comprising a base having flange, a head, and a neckcoupling the base to the head, the neck having a portion that isnarrower than at least a portion of the head; and an elongate bodyhaving first and second couplers at respective first and second ends ofthe body, each coupler including a pocket sized to receive the head of arespective one of the inserts.
 2. The stiffening assembly of claim 1,wherein each insert is integrally formed in one piece.
 3. The stiffeningassembly of claim 1, wherein the heads of the inserts each include voidsat its distal end.
 4. The stiffening assembly of claim 1, wherein theinsert is partially hollow.
 5. The stiffening assembly of claim 4,wherein the insert includes a cavity opening at the base.
 6. Thestiffening assembly of claim 5, wherein the inserts include ribsprojecting into the cavity.
 7. The stiffening assembly of claim 1,wherein the couplers are separately formed and attached to the elongatebody, the couplers and body including corresponding tabs and detents forattachment.
 8. The stiffening assembly of claim 1, wherein the elongatebody defines first and second openings at the first and second ends, thefirst and second openings receiving the first and second couplers. 9.The stiffening assembly of claim 1, wherein the pockets are defined by aplurality of fingers, the plurality of fingers being moveable between afirst state and a second state, the plurality of fingers moving radiallyinwardly from the first state to the second state, the first and secondopenings sized to cause the plurality of fingers to move to the secondstate as the fingers are received within the openings.
 10. Thestiffening assembly of claim 1, wherein the elongate member includes twotubular members defining the first and second ends and at least a thirdend, and further comprising a third insert and a third coupler at thethird end.
 11. A fuel tank assembly comprising: a fuel tank having awall defining a tank interior; and the stiffening assembly of claim 1,wherein a first exterior portion of the wall carries the first insertand a second exterior portion of the wall carries the second insert, andwherein the body and couplers are received within the tank interior. 12.The fuel tank assembly of claim 11, wherein the wall is interposedbetween the inserts and the couplers.
 13. A method of manufacturing afuel tank, comprising the steps of: forming a fuel tank, wherein thetank carries at least a first and second insert; locating a rigidconnector within the tank interior, aligned with the first and secondinserts, the connector including a first coupler and a second coupler;and coupling at least a portion of the first insert with the firstcoupler and at least a portion of the second insert with the secondcoupler, and wherein the connector spans between two spaced apart wallportions of the tank to limit movement of the two wall portions relativeto each other.
 14. The method of claim 13, wherein the forming stepfurther comprises overmolding the insert while the fuel tank is in aparison form.
 15. The method of claim 14, wherein the forming stepfurther comprises shaping a tank wall carrying the insert so that theinsert defines a projection that extends at least partially radiallyinwardly into a tank interior.
 16. The method of claim 13, wherein thefuel tank is formed in a mold having portions moveable between open andclosed positions, and the step of coupling the insert with the firstcoupler is accomplished by movement of the mold portions toward theirclosed position.
 17. The method of claim 13, wherein the interior of theparison may be accessed during the tank forming process to allowinsertion of the connector into the parison interior.
 18. The method ofclaim 13, further comprising the step of coupling the first and secondcouplers to the connector.
 19. The method of claim 18, wherein the firstcoupler is coupled to the connector simultaneously with coupling thefirst coupler to the first insert.